Thomas vaeney



THOMAS VARNEY, or SAN raAno sco', cALIr ouum, Assmsoaro THE email: POWDER ooMraNrAnD run ATLANTIC GIANT POWDER conraur, or sham reach.

lWlPRQVEiVlENT IN EXPLQSi communes.

Specification forming part of Letters Patent No. 139,746, dated J use 10, 1873; applicaticgl I l I J mm 4, 1873.

To all whom it may concern Be it known that I, THOMAS VARNEY, of the city and county of San Francisco, and

State of California, have invented an Imder as well as all other like ex )lOSlVB coma Y pounds, when frozen, explode much more easily if granulated or pulverized than when in the solid state. These frozen compounds are also much more safe and convenient for use when in the pulverized state.

It is very desirable, and the general practice, to use this class of explosives in cartridges, being paper tubes filled with powder well packed.

The cartridges are necessarily somewhat less in diameter than the borehole. In charging the hole the cartridge is rammed until it is made to fill thebore and leaveno space. This is absolutely essential in order to make the full force of the powder available, this cannot be done when the. cartridges are frozen. The powder freezes at a temperature below about 42 Fahrenheit, and the cartridges thus prepared become hard. In the ordinary winter weather of all theUnited States, except perhaps a few 'of the extreme southerly ones, the,.p0wder thus freezes and hardens. In this condition it is practically useless.- It cannot be compressed into the bore-hole so as to make it tit and till the hole, nor can it be exploded without great difli culty. a y

For these reasons the usual practice has been to thaw it before using it. At a moderate temperature it thaws very slowly, but if the temperature be so high as to thaw it rapidly the powder is liable to be injured by evaporation, and it the heat be increased and continued sufficiently it will take fire and sometimes explode.

.To avoid these and other difficulties is the purpose of my invention. It is as follows: During the process of manufacture the ingre- But dients of which the powder is formed and the powder itself when finished are unfrozen. In this state I expose it to any convenient temperature that will freeze it, and while it is freezing 1 cause it to be disturbed and broken up so constantly and thoroughly that it is prevented from adhering and hardening into a, solid mass. This may be done by stirring, sitting, or otherwise agitating and breaking it as it hardens.

If it be sifted once through a coarse sieve just before it congeals, and be allowed to fall lightly and lie loose and undisturbed. until it freezes, its particles will be found to adhere to each other slightly; but it maybe easily crumbled into dry coarse powder, and thus made to answer the purposes of-mfy invention verywell; but in order to obtain the best result the powder must be constantly stirred or otherwise agitated until the particles harden and will not adhere to each other. The agitation can be effected by hand or any proper machinery. By this means the powder can be made as fine and mealy as desired.

A solid .mass of frozen powder may-be crushed and pulverized into the same coudition as when granulated while freezing; but the expense and possible danger attending this method, and especially when the powder.

is very hard, forbids its general use. It is better to thaw it, and then treat it as. though it had not been frozen. But in thawing it great care must be taken to do it gradually, for the reasons already stated. When once thus frozen and granulated, the powder'can be kept in this state for any length of time by not allowing it to thaw. Inthis form it can be transported, handled, poured and rammed into bore-holes, either in bulk or inca-rtridge's,

with entire safety, and the utmost conven' ience.

But its great advantage lies in the fact that it can be exploded with certainty by a cheap and simple means. This means consists of an exploder in every respect like those used to explode these compounds when unfrozen, except that it should be somewhat stronger. The percussion-cap commonly used o explode unfrozen dynamite,

with about three tinie'sits ordinal; quantity of fulminate,- makes the most cheap and convenient and best explode: known to me.

{living thus described my invention, what 5 I claim as new, and desire to secure by Letters Patent, is- Thepzoeess 0f grannlating or pulverizing dynami teg nd similar compound-s 0fnitr0-glye- I pounds are rendered niore erine with-absorbent matter, by treating them while freezing in the manner substantially as hereinbefore set forth, whereby such comand more efiicient in use.

THOMAS VARNEY. v Witnesses:

ARNOLD FULLER, JORDAN W. BOPER.

easy of explosion 

